Road users increasingly rely upon traffic flow information to inform them of any incidents which may affect travel time on a journey, and to help plan travel. Such information may be provided to a user during navigation along a route via an in-car navigation device, such as a PND or integrated device, or may be provided as an input to an Advanced Driver Assistance System (ADAS). Traffic information may also be used for route planning, e.g. by a navigation device or ADAS, before commencing a journey, or to recalculate a fastest route during a journey if conditions change en route. The information has conventionally been based on messages sent over an FM radio network via the Traffic Message Channel (TMC), which may be received by navigation devices and conveyed to a user, or otherwise used by an ADAS or navigation system. A typical TMC message would include information identifying a geographic location, type and direction of an incident according to certain standard codes.
More recently other traffic information systems have been developed, such as the “HD Traffic™” system developed by TomTom International B.V., which relies at least in part upon other sources of traffic information. For example, the HD Traffic system is based upon so-called “probe” data, obtained from mobile phones, PNDs and other devices having positioning capability located in vehicles, which can be used to identify locations and speeds of vehicle, and thus indicate traffic conditions. However the HD Traffic system typically still uses TMC or similar third party traffic messages in conjunction with data obtained from analysing movements of probe vehicles.
The Applicant has realised that while the above systems have improved the accuracy with which traffic information can be provided, there remains scope for improvement in methods and systems for providing traffic information to users and/or navigation devices or ADAS, in particular which rely at least in part upon traffic messages, e.g. from third party providers or other sources. For example, TMC or similar messages are often inaccurate, e.g. in terms of identifying a location or extent of the problem, and may not be up to date.